The internal combustion engine has powered the world for over a century. This basic engine design puts the cylinder under a compression load, thus heating the air charge contained within cylinder. The internal combustion engine can be of two different designs, compression ignition or spark ignition. In the compression ignition engine, the fuel is directly injected into the combustion chamber where the heated air charge due to the compression has enough thermal energy to ignite the fuel. In the spark ignition engine, the fuel is delivered into the intake manifold or directly injected into the combustion chamber, the compression heats the air charge, but the thermal energy from the compression is not enough to ignite the fuel. The spark that is generated from a transformer is used to ionize the spark plug electrodes creates plasma that has enough thermal energy to ignite the fuel.
Both of the above described engine designs are thermal engines that are powered by fuel stocks that are hydrocarbon based. These hydrocarbon-based fuels contain hydrogen atoms and carbon atoms that are arranged in chains. When these high energy chains are put under enough load, the chains will break apart and, in the presence of oxygen, will recombine with the oxygen forming a low energy molecule. When the high energy chain is converted to a low energy molecule, energy in the form of heat is created. This thermal energy heats the working fluid (e.g., nitrogen), which expands and pushes the piston down to produce torque on the crankshaft. When these hydrocarbon chains are ignited and burned, carbon compounds are produced. For the most part, these carbon compounds are pushed out of the exhaust under pressure to the atmosphere. Those carbon compounds that are not pushed out the exhaust go by the piston rings becoming crankcase blow by or go into the intake manifold (also referred to as the “air induction system” or “induction system”) when the intake valve opens. The carbon compounds that go into the crankcase are pulled into the intake manifold through the Positive Crankcase Ventilation (“PCV”) system. Additionally, the PCV system allows some of the lubrication oil compounds to enter into the air induction system.
In either case, carbon compounds end up entering into the induction system of the running engine. One molecule after another molecule, the carbon compounds attach to the surfaces in the internal combustion engine, including the air induction system. Over time these carbon compounds build up on the surfaces of the engine. When the carbon layers become large enough to disrupt the air charge moving through the intake track into the cylinder, the combustion efficiency of the cylinders are lowered which, in turn, lowers the cylinder pressure. Since the fuel releases thermal energy that heats the nitrogen within the cylinder, variations in the air/fuel charge changes the pressure within the cylinder. These lowered cylinder pressures or lower combustion efficiencies lower the torque at the crankshaft thus lowering the engine's performance.
Different engine configurations, fuel stocks, engine loads, engine running times, and engine running temperatures change the rate that the carbon compounds build up within engines. This indicates that these variables change the time intervals that an engine will need between induction cleaning. What is needed is apparatus for and a method in which the carbon compounds accumulation within an engine can be accurately judged.
In U.S. Pat. Nos. 7,801,671 and 7,899,608 to Pederson, a method of identifying one or more misfires occurring in an internal combustion engine is disclosed. The apparatus and methods disclosed in the Pederson et al. patents can be used to determine combustion efficiency. Such equipment and methodology, however, is for a trained technician. For instance, it requires someone of relatively significant skill to find and connect a monitoring device to the ignition coil and interpret acquired data to determine the carbon compound build up within the engine.